Abrasive device



June 7, 1932. F. o. ALBERTsoN E'r AL 1,861,773

ABRASIVE DEVICE Filed Dec. 3l, 1928 rms o. nnnnnrson Ann eusrnv A.

vPaterated .lune 79 i932 narrar este f1.1

' naam- 1' L LSEN, 0F SIOUX CITY, IQWA. ASSIGNORS T0 LBERTSON & GOMPANY, ING., 0F SIOUX CITY, IOWA, .A OOREORATIONOF IOWA.

`- 'f In ZDIEW'IGEv y Application med-December 81, 1928. Serielle, 829Mo.

.,The present invention relates to abrasive devicess and is articularly concerned with the provision 'o devices for finishing and smoothing Operations.

In the finishing or smoothing operation on automobile bodies or the like, it is important that the abrasive` deviceused shall have no exposed parts 4which are capable of scratching or marring the work; and it is also important il@ that l.the abrasive pad shall have the exact degreep fp'exibility for the particular coat opint or' varnish which has just been apsl p 1e f y v It is diilicult to appreciate the importance of this precise degree of flexibility in the supporting pad, except by actual practice, but it is found that a smoothing operation which might otherwise take fifteen or twenty minutes with a pad that is too soit maybe accomplished with a pad of proper iiexibility and hardness in a very small fraction of that time. On the other hand, it the pad is too stift or hard, too much material will inevitably be removed from spots, and itmay even be necessary to repaint or revarnish the work. rlhe relative hardness .ore a coating varies with the thickness of the 'particular coat and the drying` conditions to which it has been subjected up to the time oi the smoothing operation.

As a specic example of a smoothing op eration where the degree oi flexibility is very important factor, the case of smoothing down what is commonly known in the parlance oi: those skilled in the art as an orange peel, will be described hereinafter.

orange peel may be formed where the paint or varnish has run or has been applied in overlapping coats, and this portion of the coating may be extremely' hard so that a soit pad will scarcely touch it, or it may he so soft that a stiii pad will: cut through it at once, marring the work and removing too much of the coating, so that retouching or art, by inspection, and a light application of the abrasive disc with the smoothing compound used. A, skilled operator may then Yadiust the iiexibility of the pad to the required degree dictated by his experience, and the smoothing operation may be accomplished successfully and with a minimum expenditure of time.

One of the objects of the invention is the provision of an abrasive pad in which the vstili'ness, hardness and iexibility may be varied to suit the needs of the work in order to prevent mari-ings and to expedite the smoothing operatie Another object is the'provision of a peculiarly simple and eective abrasive covering for a pad which is capable of use on both sides, and which is so cheaply constructed that the whole covering may be thrown away when the abrasive is incapable of further use.

Another object is the provision of a simple and eiective abrasive disc for pads, which is reinforced and supported by fabric in such manner that the entire working surface of the disc may he used and there are no prod jecting parts near the disc which might mar or scratch the worlr.

Another object is the provision of an abrasive covering ior pads, including a cloth for covering the edge ol the pad for use in buiiing or cleaningI small areas during the smoothing operation when it is desired to clean the surface free of smoothing compound for the purpose of examining the work.

Other objects and advantages oi the invention will be apparent from the following description and from the accompanying drawing` in which similar characters of reference indicate similar parts throughout the several views.

Referring to the drawing, of which there is one sheet;

Fig. l is a rear view of a portion of our abrasive device;

Fig. 2i is a middle sectional view of the same;

Fig. 3 is a front view, partially broken away at a plurality of points, to show the differentlayers of the abrasive device.

The abrasive device of the present invention preferably includes a covering member indicated in its entirety at 10, and a supporting member or disc indicated in its entirety at 11, and supporting member. 11 may be embodied in many different forms, While still utilizing the important features of this invention. The supporting member 11 preferably has the property of flexibility, so that the portions near its periphery may be bent to conform to the surface of the Work, and the supporting member should also be resilient and adapted to give locally, like a pad of felt, rubber or the equivalent.

One form of the supporting pad 11 is shown in Fig. 2 and this pad includes a hub 12 provided With a supporting flange 13 carrying a supporting disc 14. rlhe hub 12 may be provided with a threaded bore 15 for securing the hub to an arbor, and with a. counterbore 16 forming an annular shoulder 17 for determining the final position of the hub on the arbor.

The supporting disc 14 is secured to the hub 12 by a plurality of rivets 18 and the supporting disc 14 carries a disc 19 of felt or other flexible material secured to the metal disc 14 by a plurality of rivets 20. The felt disc 19 is in turn secured to a felt pad 21 by an annular row of stitching 22 and the felt pad 21 covers the entire Jforward surface of the supporting member 11, enclosing and protect-ing the heads of the rivets 20, and it will thus be observed that the felt pad 21 is secured to the hub and metal disc 14 Without having any metal parts on the forward surface of the felt pad.

The felt disc 19 and felt pad 21 are adapted to give locally over any small area and to provide a resilient backing for the abrasive covering 10, and both of these felt members are also adapted to flex backward to conform to the surface of the Work when pressure is applied to the rotating member by the operator. The metal disc 14 may have its outer edge curved backward as at 23 to permit a greater flexing movement of the felt pad 21 and to prevent the edge from cutting into the felt disc 19.

The abrasive covering 10 is preferably so cheaply constructed that when its abrasive surface is no longer capable of use, the entire covering may be thrown away without serious loss. and for this purpose I provide a circular piece of fabric 24 such as cambric, the outer edge 25 of which is protected by buttonhole stitching or any other economical form of binding.

ln order that the one piece of cloth may give a maximum of service, and to give the required degree of stiffness` we provide both sides of the cloth 24 with a circular piece of abrasive material 26 and 27 such as sand or emery paper or cloth or tl e like, and the abrasive discs 26 and 27 are cemented to the cloth 24 by a cement which is not affected by moisture or the smoothing liquid used in automobile nishing;

The cloth 24 reinforces and supports the abrasive dies 26 and 27, and both sides of the abrasive covering 10 may be used, so that a double service covering is provided.

The abrasive discs 26 and 27 are preferably of substantially the same diameter as the felt pad 21, so that the cloth 24 may be drawn back overthe pad 21 and secured by a tension member 28. The tension member 28 consists of a cord which is threaded alternately from side to side through the cloth 24 about its periphery, and when the cord 28 is drawn tight on the back of the felt pad 21, the abrasive covering 10 is securely fastened on the pad.

It should be noted that the outer edge of the pad 21 is covered by cloth so that if the operator desires' to momentarily clean a portion of the Working area, he can do so by merely touching the cloth edge against the work so that he can see the work free of the smoothing compound, and then proceed to` correct any defects which he may have observed.

One of the most important features of the present invention is the provision of a flexible and resilient abrasive device having means for varying the degree of flexibility or hardness of the pad, and this may be accomplished by providing a plurality of flexible, yet slightly stiff discs of Celluloid, isinglass or the like, between the pad 21 and the abrasive covering 10. The celluloid discs 29 also protect the pad from the smoothing compound or liquid, and as previously described, these discs may be removed or inserted to change the flexiblity and hardness of the whole pad. For very soft coat-ings of paint or varnish, most of the dises 29, or all of them, may be omitted and the pad is thereby given a softness and flexiblity which is perfectly adapted for use on the softest paint coating which any operator may encounter, but where the orange peel is unusually hard, the operator may quickly untie the cord 28 and insert a plurality of the discs 29 to give the pad the required hardness and stiffness necessary to smooth down the orange peel quickly.

rlhe operating time 1n a particular case may be reduced to one-twentieth of the time which would be required if the exibility of the pad could not be changed to suit the conditions, and at the same time the operator en abled to use the same pad on work which requires a very soft and flexible pad.

The Celluloid discs 29 are flexible and capable of ben din g with the pad, but theaddition of each Celluloid disc reduces the flexibility by a slight degree, and if enough discs are employed, the pad becomes quite stiff. The celluloid discs also adjust the relative hardness of the pad because they distribute the pressure over a larger area of the pad, and

thereby prevent thepad from givin locally as the otherwise soft felt pad woul do.

It will thus be observed that we have invented an abrasive device which is peculiarly adapted to be used eiciently on all kinds of smoothing work, and particularly on automobile bodies. Our abrasive device includes means for adjusting the flexibility and the relative hardness or softness of the pad, as well as a novel and economical form of the abrasive covering capable of giving double service, and so cheaply constructed that the entire covering may be thrown away when the abrasive surface is no longer capable of use.

Our abrasive device has no projecting parts or metal adjacent the working surface which might mar the work and the entire structure is peculiarly simple and sturdy and capable of long and etlicient service.

While we have illustrated a preferred embodiment of our invention, many modifica.-

tions may be made without departing from the spirit of the invention, and we do not wish to be limited to the precise details of construction set forth, but desire to avail ourselves of all changes within the scope of the appended claim.A

Having thus described our invention, what we claim is new and desire to secure by Letters Patent of the United States, ist

An abrasive device, comprising a supporting hub, a resilient and exible pad carried by said hub and adapted to iex relative to said hub, a plurality of thin and exible discs located-on the face of said pad for providmg said pad with a predetermined degree of flexibility and local resiliency, a covering for said pad and discs comprising an abrasive member enclosing said discs and pad, andmeans for securing said covering to said pad adjacent the outer edge of said pad to permit said' pad to flex freely under pressure applied to said abrasive device.

In witness whereof, we hereunto subscribe our names this 17 day of Dec., 1928.

FRANS O. ALBERTSON. GUSTAV A. OLSEN. 

